Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset

Due to the harsh natural environment on the Tibetan Plateau (TP), its vegetation is sensitive to climate change. Therefore, it is essential to characterize long-term vegetation shifts for understanding of land surface processes across the TP. Gradual greening or browning growth in vegetation greenne...

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Main Authors: Yong Ni, Yuke Zhou, Junfu Fan
Format: Article
Language:English
Published: IEEE 2020-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/9044740/
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spelling doaj-3652bf163437400d9a162cf807f387b82021-03-30T03:11:31ZengIEEEIEEE Access2169-35362020-01-018565185652710.1109/ACCESS.2020.29826619044740Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g DatasetYong Ni0Yuke Zhou1https://orcid.org/0000-0002-2559-0241Junfu Fan2https://orcid.org/0000-0001-8987-7930State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Science and Natural Resources Research, Chinese Academy of Sciences, Beijing, ChinaKey Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, ChinaSchool of Civil and Architectural Engineering, Shandong University of Technology, Zibo, ChinaDue to the harsh natural environment on the Tibetan Plateau (TP), its vegetation is sensitive to climate change. Therefore, it is essential to characterize long-term vegetation shifts for understanding of land surface processes across the TP. Gradual greening or browning growth in vegetation greenness is detectable while the alternating process between greening and browning, its timing, and type remain unclear. In this paper, breakpoint in time series of a satellite-derived vegetation index was detected at pixel-level during 1982-2012. The long-term growth procedure of vegetation was then characterized by combining the greening/browning trend for the two sub-periods, on each side of the breakpoint. The combinations of greening/browning status were classified into three categories (monotonic, interrupted and growth reversal). Possible causes for abrupt vegetation changes are discussed in the content of climate change and grassland management. Results show that breakpoints are temporally widely distributed and have significant spatial heterogeneity. About 21% (11%) of the vegetated area showed significant greening (browning) trends. Vegetation in central and eastern TP has tended to be greening. Browning trends were particularly evident in the southern and northeastern TP and were scarce in the west. About 32% of the vegetation was found to change significantly in this analysis. Greening trends occurred more often than browning trends and exhibited both a monotonic and an interrupted growing process. Trend reversal in vegetation was dominated by declining trends. Breakpoints in monotonic and interrupted trends were concentrated in some time points, but those with reversal trends were discretely distributed over time span. Among different ecosystem types, desert ecosystems presented the most significant greening trends, accounting for 53% of plant-covered desert. Conspicuous degraded trends were identified on alpine sparse vegetated area. Statistically, breakpoints in precipitation and air temperature are not consistent with those in vegetation greenness index. And grazing projects have not posed a significant effect on abrupt shifts in vegetation greenness.https://ieeexplore.ieee.org/document/9044740/Tibetan Plateau (TP)greening and browningbreakpointsseasonal-trend modelGIMMS NDVI3g
collection DOAJ
language English
format Article
sources DOAJ
author Yong Ni
Yuke Zhou
Junfu Fan
spellingShingle Yong Ni
Yuke Zhou
Junfu Fan
Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset
IEEE Access
Tibetan Plateau (TP)
greening and browning
breakpoints
seasonal-trend model
GIMMS NDVI3g
author_facet Yong Ni
Yuke Zhou
Junfu Fan
author_sort Yong Ni
title Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset
title_short Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset
title_full Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset
title_fullStr Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset
title_full_unstemmed Characterizing Spatiotemporal Pattern of Vegetation Greenness Breakpoints on Tibetan Plateau Using GIMMS NDVI3g Dataset
title_sort characterizing spatiotemporal pattern of vegetation greenness breakpoints on tibetan plateau using gimms ndvi3g dataset
publisher IEEE
series IEEE Access
issn 2169-3536
publishDate 2020-01-01
description Due to the harsh natural environment on the Tibetan Plateau (TP), its vegetation is sensitive to climate change. Therefore, it is essential to characterize long-term vegetation shifts for understanding of land surface processes across the TP. Gradual greening or browning growth in vegetation greenness is detectable while the alternating process between greening and browning, its timing, and type remain unclear. In this paper, breakpoint in time series of a satellite-derived vegetation index was detected at pixel-level during 1982-2012. The long-term growth procedure of vegetation was then characterized by combining the greening/browning trend for the two sub-periods, on each side of the breakpoint. The combinations of greening/browning status were classified into three categories (monotonic, interrupted and growth reversal). Possible causes for abrupt vegetation changes are discussed in the content of climate change and grassland management. Results show that breakpoints are temporally widely distributed and have significant spatial heterogeneity. About 21% (11%) of the vegetated area showed significant greening (browning) trends. Vegetation in central and eastern TP has tended to be greening. Browning trends were particularly evident in the southern and northeastern TP and were scarce in the west. About 32% of the vegetation was found to change significantly in this analysis. Greening trends occurred more often than browning trends and exhibited both a monotonic and an interrupted growing process. Trend reversal in vegetation was dominated by declining trends. Breakpoints in monotonic and interrupted trends were concentrated in some time points, but those with reversal trends were discretely distributed over time span. Among different ecosystem types, desert ecosystems presented the most significant greening trends, accounting for 53% of plant-covered desert. Conspicuous degraded trends were identified on alpine sparse vegetated area. Statistically, breakpoints in precipitation and air temperature are not consistent with those in vegetation greenness index. And grazing projects have not posed a significant effect on abrupt shifts in vegetation greenness.
topic Tibetan Plateau (TP)
greening and browning
breakpoints
seasonal-trend model
GIMMS NDVI3g
url https://ieeexplore.ieee.org/document/9044740/
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